Restaurant critics are, by nurture, rampant neophiliacs. We are so constantly bombarded with information about new openings that, like the royal family, we could be forgiven for thinking dining rooms are meant to smell of drying paint. And yet, of course, it is the latest ventures which are the least tested and the old stagers which actually know what they are doing. At the beginning of a year guaranteed to bring the usual avalanche of novelty dining concepts - Bolivian-Turkish fusion, say, or menus made up entirely of dishes formed from rare varieties of bird spit - it is worth reminding ourselves that the old ones can still be the good ones.

And so to Oslo Court, where menus for the ladies don't carry prices, and you can have your napkin in any colour you want as long as it's salmon pink; where no scallop has ever suffered a searing, and the kitchen's daily cream order is big enough to give a sizeable herd of Friesians severe udder-ache; where grapefruit is still served grilled with brown sugar, Diane is the name of a steak, not a waitress, and gay means happy. Believe me: when it is lunchtime in London, it is 1977 at Oslo Court.

The restaurant has been trading, in various incarnations, since the Second World War and occupies a curious site on the ground floor of a residential mansion block in London's St John's Wood. For many years, this guaranteed a particular clientele. The place used to be full of mittel-European Jews celebrating their 80th birthdays. A few years ago I was on a restaurant-awards judging panel and we were trying to decide between a classy, new French restaurant and Oslo Court for the best service award. 'Can you imagine the French place dealing with 100 Jewish pensioners complaining about absolutely everything?', one of my co-judges asked. The award went to Oslo Court.

On the evidence of this latest visit, the old Jews have gone, to be replaced by tables of bald-headed men, quickly turning the same colour as the tablecloths, and jolly women of the sort Beryl Cook likes to paint. But the twinkling waiters are still there in their dinner jackets, bouncing up to the table with the kind of light skip favoured by television game show hosts making an entrance. They are almost all men. The only woman in the dining room is there to take: she takes your coat, she takes your empty plates, she takes away the crumbs you have left behind. It is the men who bring the food.

And keep bringing it, for it is illegal, by act of parliament, for anybody to leave Oslo Court feeling merely replete. At Oslo Court they assault you with food. They pelt you with it, feed you up like the Cossacks have set siege to the city. No wonder the Jewish mothers loved it. For the amount you get, the three-course price of £26.50 at lunch and £38 at dinner seems very reasonable; frankly, that price wouldn't be bad for the leftovers. And yes, some of it does remind us why a lot of it has been swept away by fashion. Side dishes of limp mangetout and over-boiled endive were grim, for example. But so much else here makes up for it - not least the roast potatoes, which are the real thing. You know by now how much that means to me.

The menu is huge - there are 15 or 20 starters and the same number of mains, all of them supplemented by a long list of specials which the waiters reel off with immense ease, not least because most of them are on every day. For example, there is a lobster cocktail, at a modest supplement of £3.50. It boasts most of a tail, both claws, a bed of crisp iceberg and a jug of Marie Rose sauce, all served over ice. What's not to like? Coquille St Jacques looks like a picture from Robert Carrier's Great Dishes of the World - a large shell, holding a dome of crisply browned mash. Underneath that, in a cream sauce which is surely on the British Heart Foundation's proscribed list, is a generous mixture of scallops and prawns.

For our main courses we tried an unfinishable half a crispy duckling, which would have been at home between some Chinese pancakes (high praise indeed), and a Wiener Holstein, one of those dishes that is rightly starting to make a comeback: a thin veal escalope, breaded and fried, decorated with capers, anchovies and a fried egg. Naturally, desserts come from a trolley not a kitchen, are of the trifle and gateau variety, and are served by a waiter who knows more about a good mince than the meat counter at Sainsbury's. We managed a creme brulee with an exceptionally good creme. Finally came a plate of chocolates and Turkish delight, and the first signs of heart failure.

Happily, though, Regent's Park is just outside the door. And so we decided it would be best if we walked back into the centre of London - and the 21st century.